21968478499 has 4 divisors (see below), whose sum is σ = 23965612920. Its totient is φ = 19971344080.

The previous prime is 21968478473. The next prime is 21968478529. The reversal of 21968478499 is 99487486912.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21968478499 - 2¹¹ = 21968476451 is a prime.

It is a super-2 number, since 2×21968478499² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21968478449) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 998567194 + ... + 998567215.

It is an arithmetic number, because the mean of its divisors is an integer number (5991403230).

Almost surely, 2^21968478499 is an apocalyptic number.

21968478499 is a deficient number, since it is larger than the sum of its proper divisors (1997134421).

21968478499 is a wasteful number, since it uses less digits than its factorization.

21968478499 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1997134420.

The product of its digits is 62705664, while the sum is 67.

The spelling of 21968478499 in words is "twenty-one billion, nine hundred sixty-eight million, four hundred seventy-eight thousand, four hundred ninety-nine".